Wideband temperature calibrated avalanche noise source for industrial radiometers

This paper presents the development and characterization of a wideband noise source, involving Commercial Off-The-Shelf components. The noise source relies on avalanche noise generation by driving the base-emitter junction of a packaged Si-Ge Heterojunction Bipolar Transistor into reverse breakdown. The paper discusses the noise source operation principle and its extensive characterization in both mm-Wave K band, as well as in C and X bands. Two prototypes were implemented without including output impedance matching, such as to preserve the wideband capabilities of the noise source. Performances were validated in terms of output Excess Noise Ratio (ENR), values reaching 10.8 dB were obtained for the K band at 6.71 mA breakdown current, in a 24-32 GHz bandwidth and device temperature excursion. A calibration model is also provided, which fits ENR fluctuations with an average error under 0.05 dB, when considering the maximum current and temperature excursions, as compared with 0.8 dB ENR drift reported for the non-calibrated source. The C and X band validation in 4-6 and 10-12 GHz frequency ranges highlights ENR reaching 25.6 and 22.6 dB, respectively, at 6.9 mA bias current.